Pigging systems are installed on pipeline systems for the purpose of inserting a pipeline pig without interruption of the pipeline flow. Pipeline pigs are typically sized to the nominal pipeline diameter and configured of different designs and materials to serve the purpose of cleaning, liquid removal, drying, batching, chemical treatment, or inspection. Traditional pigging systems (sometimes known as launchers and receivers) have been utilized for decades to insert and retrieve pipeline pigs without interrupting the product flow. The launcher is installed upstream in the traditional pigging system and the receiver unit is installed downstream of the section of the pipeline to be pigged.
FIG. 1A illustrates a pig launcher 10 according to the prior art, and FIG. 1B illustrates a pig receiver 20 according to the prior art. Briefly, the launcher 10 has an oversized barrel section 11 connected by an eccentric reducer 12 to a nominal line section 13. A closure 14 on the barrel section 11 provides access to its interior for inserting a pig (not shown). The line section 13 has a flange 16 for connecting to a line pipe of a piping system. The barrel section 11 includes a blow-down connection 18A, a kicker connection 18B, and a drain connection 18C. The line section 13 includes a pig signaler 15 and a vent 17.
The receiver 20 is similar and has a nominal line section 23 connected by a concentric reducer 22 to an oversized barrel section 21. A closure 26 on the barrel section 21 provides access to its interior for removing pigs (not shown). The line section 23 has a flange 24 for connecting to a line pipe of the piping system. The barrel section 21 includes a blow-down connection 28A, a bypass connection 28B, and a drain connection 28C. The line section 23 includes a pig signaler 25 and a vent 27.
These units 10, 20 are isolated from the mainline with isolation valves (not shown) to allow the pressure to be released and the product drained or vented so that pipeline pigs can be inserted or retrieved from the pipeline system with no pressure or product in the launcher 10 and receiver 20. Such traditional units 10, 20 of the pigging system as shown in FIGS. 1A-1B are manually operated to launch and receive a single pipeline pig for each pigging operation.
Other pigging systems in the art have an automated pig launcher that can provide improved pipeline flow efficiency, cost savings, and safety by not requiring each pig to be loaded individually. To date, automated pig launchers use a vertical or angled design orientation where the pipeline pigs are gravity fed to the downstream launch mechanism. In particular, the existing launch mechanism has two pins that are retracted by means of hydraulics or pneumatics allowing the pipeline pig to be launched by gravity. Additionally, current automated pig launchers are designed for a specific type of pig and product type.
Because current automated pigging systems are gravity fed, the systems need to be elevated at an installation. This requires the installation to have a platform to provide access to the system components and requires lifting equipment to be used for the operation of the unit. Additionally, because current automated pigging systems use hydraulics or pneumatics to actuate launch mechanism, the existing system requires supply gas to drive the hydraulics, which complicates the installation and its operation. In fact, the controller for these current automated pigging systems can be complex, making them harder to operate and maintain.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.